When you dissolve a strong electrolyte in water, it shatters completely into ions. A weak electrolyte behaves in a completely different way. It only lets a small fraction of its molecules split apart.
The rest of the molecules stay firmly stuck together in the liquid. Pure liquid water cannot conduct an electrical current on its own. It needs loose ions to carry the moving electrical charge.
Because weak electrolytes produce very few ions, they conduct electricity very poorly. Many common household liquids actually contain these types of weak electrolytes. Weak acids like the acetic acid in vinegar are a perfect example.
Weak bases like the ammonia used in window cleaners also fit this group. A common student mistake is mixing up concentration with electrolyte strength. You can have a highly concentrated solution of a weak electrolyte.
It will still conduct electricity poorly because most molecules refuse to split. Temperature can change exactly how many molecules decide to split apart. Heating the liquid usually creates a slightly larger number of loose ions.
You can also force a higher percentage of molecules to split by adding more water. This strange effect is known in chemistry as Ostwald’s dilution law. Even though more water dilutes the mixture, it encourages the molecules to break apart. Chemists use a special number called an ionization constant to measure this splitting behavior.